Display devices having a planar display surface such as liquid crystal displays have been combined with position detecting devices. The position detecting device is disposed on the display surface of the display device so that an image output by the display device and a position input can easily be associated (see, for example, Japanese Patent No. 2139446).
The position detecting device used for the position input is typically an electromagnetic induction-type position detecting device. The electromagnetic induction-type position detecting device is able to detect the position of the position indicator even when the position indicator is a distance away from the surface or not in contact with the surface. Hence, there are also display/input devices having the electromagnetic induction-type position detecting device disposed at the rear-surface side of the display device (see, for example, U.S. Pat. No. 4,988,837).
When a position indicator is used to input a position, detection coils may be provided as close to the position indicator as possible so that detection can be performed with high accuracy. To this end, detection coils have been positioned on the display surface side of the display device using ITO (indium tin oxide), or other transparent members. Additionally, when employing an electromagnetic induction-type position detecting device, a single coil has also been used to perform both detection of signals using the position indicator, and supply electric current to the position indicator.